The present invention generally concerns improved ergonomic conditions for seated persons (for example, such as keyboard operators or wheelchair patients), and more particularly concerns improved devices for support of a keyboard or the like on either a desktop surface or a user's lap so as to prevent repetitive motion injuries and cumulative trauma disorders for such users.
The literal explosion of computer applications in the workplace has resulted in the creation of numerous jobs which require keyboard operations. For example, certain data entry occupations may routinely require the keyboard operator to make ten thousand keystrokes or more per hour. Additionally, automated monitoring of a worker's output (i.e., keystroke rate) can create a considerably stressful work environment.
Routine exposures to such work environments has led to various occupational diseases which did not heretofore exist. Many of such diseases are generically referred to as repetitive motion injuries (RMI). One example is a syndrome referred to as carpal tunnel syndrome (CTS), a nerve disorder which is characterized by inflamed tendons in the hands. Symptoms include numbness and tingling fingers, the loss of feeling, and the loss of strength in one's hands or arms. Early treatments may include rest, job changes, wrist splints that prevent unnatural movements, or application of pain killers, such as cortisone. In advanced cases, corrective surgery on the ligament or nerves may be required to alleviate the acute pain in the hands caused by pressure on the nerve that runs through the bone tunnel in the wrist. Such pressure can occur from various inflammations brought on by repetitive (even though relatively small) traumas.
Recently, repetitive strain injuries replaced skin diseases as the leading cause of occupational illnesses in the United States according to the National Institute for Occupational Safety and Health. In 1987, almost seventy-three thousand (73,000) cases were reported, representing 38 percent of all cases. The problem is widespread, and can strike other industries such as the auto industry where a worker might operate a vibrating air gun or other device which can result in various cumulative trauma disorders.
One response from the field of ergonomics (i.e., human engineering) to such conditions has generally been to alter and hopefully improve furniture to be used by operators of personal computer equipment. For example, a video display terminal might be carried on a movable arm for maximum flexibility in its positioning. Additionally, some local areas have sought to legislate standards for workplace environments so as to lesson the occurrence of RMI/CTS and other so-called "video display terminal diseases."